Careful design of the architectural features of an auditorium is of no use if either external or internal noise is loud compared with the soundof the performers. If there are neighboring airport flight patterns, railroads or highways, special efforts must be made to isolate the auditorium acoustically from the surrounding area.
Another important source of noise is air conditioning or blowers, which are often sources of white noise or noise rich in lower frequencies. These low frequencies can, in extreme cases, mask out the higher-frequency sounds of the music.